1. Field of the Invention
The present invention relates to a detachable recording head for use in a recording apparatus, and more particularly to such a recording head with a reduced number of terminals.
2. Description of the Prior Art
The conventional interchangeable recording head requires an increased number of electric terminals with the increase in number of recording elements and a particularly large number of terminals in case of achieving a higher print quality, or of printing Japanese characters with dots. Japanese characters require at least a 16.times.16 dot matrix, and a 24.times.24 dot matrix for achieving a particular print style, for example Ming style, thus requiring at least 24 dots for the head even when the printing is achieved with vertical one-column dots.
FIG. 1 shows the structure of a conventional thermal head and a connector therefor, wherein there is provided a thermal head body 1 having 24 heating elements 1a arranged on a plane, a printed circuit board 2 having circuit patterns for power supply to said thermal head body 1, a heat sink 3 for holding and cooling said thermal head body 1, an angle member 4 for maintaining the thermal head body 1 in contact with the printed circuit board 2 and with the heat sink 3, and a connector 5 for detachably maintaining the heat sink and making electrical connections to said printed circuit board 2.
Such a thermal head, containing only the resistors constituting the heating elements, requires at least 25 terminals for the connector 5, i.e. 24 terminals for selecting dots and 1 common terminal. Such an increased number of terminals, requiring an arrangement in a plane, leads to a larger dimension of the thermal head unit or to a lowered reliability due to finer circuit patterns arranged in a higher density. Also the use of a flexible cable as the power supply to the moving thermal head results in a reduction in the supply voltage, causing a defective in the function of the thermal head sensitive to the voltage fluctuation.